Saturday, September 4, 2010

CO2, Campfires and Catastrophic Global Warming

After a break for the summer, it is good to be back, writing on SLB. This has been an unusually cool summer in California with both June and August registering below the long-term "normal" temperature. July was only barely above its normal temperature.

To continue with the blog posts, I want to address a topic that has been of considerable interest to me, and also respond to a serious question that is frequently asked of me. I typically get this question in each speech I make on global warming, and California's global warming law, AB 32.

The question is, why do you (meaning me) believe so strongly that atmospheric CO2 has no impact on the Earth's average temperature, and why should anyone believe you when so many scientists say that it is not controversial that CO2 definitely heats the atmosphere?

To begin, I want to point out that before becoming an attorney, I practiced chemical engineering for approximately 25 years in the USA and several other countries. Chemical engineering is a very broad discipline, but like all engineering, it involves a mix of theory and practice. One of the key aspects of chemical engineering is designing, building, operating, modifying, and repairing fired heaters. A fired heater has multiple burners that burn some sort of gas or an oil, or a combination of both, although there are also coal-fired heaters that burn the coal as a solid or a pulverized dust. Typically, the burners are either mounted along the side walls or at the bottom. Air is also introduced into the furnace, and the fuel burns inside. The interior walls are lined with a special type of brick or refractory that is designed to reflect the radiative heat back into the firebox. The walls are usually lined with metal tubes, spaced at regular intervals not only from each other but also from the interior walls. To ensure the fired heaters operate properly, they must be designed and built properly. Therefore, engineers understand how radiative heat transfer works. There are literally thousands of fired heaters operating continuously around the world, except for brief periods for repair.

It is this background in how heat travels from a flame, to a steel tube, but also from the flame to the refractory brick wall that gives me the certainty about CO2 and Earth's warming. The steel tubes not only receive heat directly from the flame, but also from the back side via heat reflected or re-radiated from the refractory brick wall. One of the key parameters in designing fired heaters is the distances used between the various components. For example, should the tubes be spaced half an inch apart, or perhaps 4 inches, or would 12 inches apart be better? Tubes are actually more like pipes, as they are typically around 4 inches diameter and perhaps 20 to 40 feet long. Also, should the tubes be placed half an inch from the refractory brick wall, or a greater distance? Furnace designers, engineers, have worked all this out and concluded that it is not a good idea to have the tubes placed too close together, nor too close to the wall. Also, it is not a good idea to have the tubes too far apart or too far from the wall. Distance is one of the critical parameters. For those who want to see what fired heaters look like, here is a link to one designer/supplier; this is not an endorsement but is presented merely for information.

To put this in some perspective, and to bring the discussion back to CO2, one only has to consider a campfire. Having built and enjoyed thousands of campfires thus far, and hundreds more wood-burning fires in fireplaces in homes over the years, a few things have become obvious to me. First, a campfire can be very hot. Wood fires can melt lead. The flames can reach one thousand degrees F or higher. Second, even though the flames are fairly hot, one can sit a few feet away from a campfire and be comfortable. A large fire emits more infra-red radiation as heat, therefore people tend to sit a bit farther away.

But an interesting thing happens around campfires. If one sits or stands too far away, the heat is not apparent to the skin. And, that distance is not all that far. One can stand 100 feet away from a normal campfire and not feel a thing. The example I use when discussing this with others is to consider a campfire on a hill three miles away. The view to the campfire is unobstructed, so any heat from the fire has a clear shot at one's face. Nobody that I know could ever feel the heat from such a fire located approximately 15,000 feet away. This is true even though the campfire's flames are burning at more than 1,000 degrees F. Certainly, a fired heater designer would never build a heater with such long distances involved between flame and the tubes.

Yet, and this is the key, the climate scientists would have us believe that CO2 in the atmosphere, which can be considered approximately 15,000 feet above the Earth's surface for an average distance, absorbs heat from the Earth's surface and prevents that heat from escaping to space. Note that the Earth's surface is not at 2,000 degrees F or at 1,000 degrees F such as a campfire, but is typically at 100 degrees F at the maximum. Some places will be a bit warmer, perhaps 120 degrees F in a desert in summer. But a more typical temperature is 80 degrees F, for land surfaces. Most of the oceans are cooler than that, depending on which ocean and the season of the year.

The Earth therefore radiates infra-red heat upward from its surface, at approximately 80 degrees F. The CO2 in the atmosphere, even giving it a very cold temperature at altitude, of perhaps -20 degrees F, is supposed to absorb the heat from the Earth's surface. The energy absorbed by the CO2 is supposed to be sufficient to block a good portion of the heat from the Earth, and force the surface below to cool down at a slower rate than would occur otherwise. The slower rate of cooling is then supposed to evaporate more water into the atmosphere, and create an even greater heating effect.

I leave it to the reader to decide if the climate scientists have a non-controversial position with their assertion that atmospheric CO2 absorbs heat from the Earth's surface. If one cannot feel the heat from a wood-burning campfire 3 miles away on a hill with a direct line-of-sight, one can only imagine how much of the Earth's surface heat affects a CO2 molecule 3 miles up in the sky.
Roger E. Sowell, Esq.


Anonymous said...

Interesting point about distance and CO2 absorbing heat energy. I like the concept of a hot campfire not being felt 100 feet away.

By extension, then, climate scientists must believe that the heat radiated from the full moon should be perceived on Earth. The moon's surface at its mid-day is approximately 120 degrees C, or 248 deg F. Obviously there is no warming of the Earth from the full moon.

Similarly, the heat from billions of stars does not warm the Earth. Yet the stars' surfaces are millions of degrees temperature, either C or F.

Great post.

anna v said...

Hi there,
I had bookmarked your blog and found it searching for my AGW fix since wattsup seems to be down :).

Your campfire example is striking, but, as you must know, it omits the integration over lots of campfires which would be the true analogue of the earth radiating.

There does exist a "greenhouse effect" misnamed but still there, with H2O, the humidity of the atmosphere, no? Deserts are much colder at night than humidity laden plains , no?

Also should one put H2O at 15000 feet, the average troposphere, or should one weight with the mass of H20 ? On a humid day one feels much hotter than on a dry one, for the same temperature, no?

I agree that CO2 is a tiny part of this greenhouse business though.

few thoughts.

Roger Sowell said...

Anna v, I agree that the Earth's surface is radiating over a much larger area than one small campfire. Still, my point is that the radiation temperature is far less (80 F) compared to the campfire (1000 + F).

Also, there is an absorption phenomenon with CO2 - this is well known and equations exist for this for the design of fired heaters. But, the atmospheric conditions do not lend themselves to much effect, if any, from radiation absorption by CO2.

I have also noted in my experience the cold desert nights you mention, and warm coastal plains, with both having the same CO2 level. Clearly, water vapor is the dominant gas, and not CO2.

The humid air feels warmer to human skin compared to dry air because perspiration evaporation is faster into the dry air. I would also point out that firefighters use a mist, or fog, type of water spray to approach a large fire. This water spray stops the radiating heat from reaching the firefighters. Then they can spray a concentrated stream of water onto the fire.

anna v said...

"The humid air feels warmer to human skin compared to dry air because perspiration evaporation is faster into the dry air. I would also point out that firefighters use a mist, or fog, type of water spray to approach a large fire. This water spray stops the radiating heat from reaching the firefighters. Then they can spray a concentrated stream of water onto the fire."

Sure, part of it is the slower evaporation, but part of it is what the thermometer feels when it stays at 22C instead of going down to 18 for a clear night in my location at present. The distributed molecules in the air act as the plinths in your heat engines, "reflecting" the radiation from my body /changing the boundary conditions of the equations.

Anonymous said...

"If one cannot feel the heat from a wood-burning campfire 3 miles away on a hill with a direct line-of-sight"

That is because the heat has already been absorbed by CO2 before it reaches you

Roger Sowell said...

Mr. Mous, I wonder, then, where all the heat went from the campfire that is only 200 feet away. Also, please explain how CO2 absorbs all the heat, since CO2 only absorbs in a very narrow spectral band.